Gaseous electric discharge device



Oct. 10, 1933.

M. PIRANI ET AL GASEOUS ELECTRIC DISGHARGE DEVICE Filed Sept. 16, 1930INVENTORS W ATTORN EY Patented Oct. 10, 1933 UNITED STATES PATENT OFFICEGASEOUS ELECTRIC DISCHARGE DEVICE poration of New York ApplicationSeptember 16, 1930, Serial No.

482,222, and in Germany October 19, 1929 4 Claims.

The present invention relates generally to-gaseous electric dischargedevices and more particularly the invention relates to means for feedinggas replenishments to luminescent gas lamp devices similar to thosedescribed in co-pending application Serial Number 381,036, filed July25, 1929 being the invention of Marcello Pirani and Kurt Nitschke.

The gas feeding means of the application referredto comprises a gasevolving material, a heater element for said material, said heaterelement being connected into the circuit of the electric dischargedevice at a determined value of the current density of the dischargedevice by a governor connected in series with one of the electrodes ofsaid gaseous electric discharge device. With such apparatus anoversupply of gas replenishments to the tube is avoided if the currentof the circuit is steady.

The object of the present invention is to avoid an oversupply of gasreplenishments to a gaseous electric discharge device even with afluctuating voltage in the main supply source to said device.

The invention attains its object by connecting r the governor of theheater element in parallel to the electrodes of the gaseous electricdischarge device. In such an arrangement the cutting into and out ofcircuit of the heater element of the gas evolving material is controlledonly by the changes in the voltage drop across the electric dischargedevice which, as is well known in the art, depends on the gas pressurethereof, and is not affected by fluctuations in the voltage of thesupply circuit.

In the drawing accompanying and forming part of this specification threeembodiments of the invention are shown for purposes of disclosure inwhich,

Fig. 1 is a side elevational view of a gaseous electric discharge devicepartly in section, the electrical circuits therefor being shownschematically.

Fig. 2 is a side elevational View of a gaseous electric discharge deviceand a thermostatic governor, the electrical circuits therefor beingshown schematically, and

Fig. 8 is a side elevation of a gaseous electric discharge device and adifferent type of thermostatic governor, the electrical circuitstherefor being shown schematically.

Like numbers denote like parts in all the figures.

Referring to Fig. 1 the gaseous electric discharge device 1 has theusual sheet metal electrodes 2 which are connected to the secondary 4 oftransformer 4, 5 by leads 3. The primary 5 of said transformer 4, 5 isconnected to a current source, which is of the usual commercialpotentials, through a choke coil 6 and the lead 15. A rod 14 made of asintered mixture of a gas evolving material and a flux material, asdisclosed in the aforementioned application, is sealed into offsetchamber 13. Said rod 14 has a heating filament or wire 12 wound aroundit and evolves gas only when heated. Two contacts 10 are connected intothe leads 16 of the heater element 12, from which branch 011 the chokecoil 6 and the lead 15 of transformer 4, 5. When gas replenishments areneeded said contacts 10 are bridged by plate 9 attached to core 8 ofelectro-magnet 7, 8 to connect theheater element 12 into the circuit.Said electromagnet 7, 8 is connected across the main source through lead15 and choke coil 6 by leads 22 and thus is in parallel relation toelectrodes 2. As is well known in the art, a ballast device, such as achoke coil 6 operates to prevent extreme fluctuations in potential inthe heating and feeding circuits of the gaseous electric dischargedevice, and thus the electro-magnetic governor '7, 8 is not aifected byfluctuations in current supply. In the course of time the gas pressurein the operating electric discharge device 1 decreases with a consequentlowering of potential. As coil '7 of electro-magnet '7, 8 then has lesspotential, core 8 drops until plate 9 bridges contacts 10 putting heaterelement 12 in the circuit to cause the evolution of gas from rod 14.When the gas pressure has been restored to normal, the potential of theelectric discharge device 1 and the electro-magnet '7, 8 is restored tonormal, the coil '7 then has a suflicient voltage to lift core 8 andplate 9, and heater element 12 is automatically-cut out of the circuit.Thus even with a fluctuation in current intensity in the supply circuitof a gaseous electric discharge device an oversupply of gasreplenishment to the device is avoided.

The gaseous electric discharge device shown in Fig. 2 has oxideelectrodes 2' which are connected directly to the supply circuit of theusual commercial voltages by leads 3 needing no transformer. Said oxideelectrodes 2' may be heated by the line potential or by a heater elementwound around them and connected to the line potential. In thisembodiment of the invention heater element 12 is wound around acontainer 14 which has therein a pulverized gas evolving material. Thegovernor is a thermostatic switch consisting of a chamber 23 containingan inert gas, a quantity of mercury 25 suflicient to bridge contacts 10and having sealed therein a heating coil 24. Said heating coil 24 isconnected in parallel to electrodes 2 by leads 22 so that the heatradiated by coil 24 is governed by the potential of the dischargedevice 1. If this potential decreases, caused by a loss of gas pressure,less heat is radiated from heating coil 24 so that the gas pressure inchamber 23 is reduced which permits mercury 25 to shift to such positionthat contacts 10 are bridged. As in the heating circuit of Fig. 1 heaterelement 12 then remains in the circuit until normal gas pressure isrestored in the gaseous electric discharge device 1.

The gaseous electric discharge device and the circuits therefor shown inFig. 3 are similar to those of Fig. 2 with the exception of thethermostatic governor. In this figure the thermostatic governorcomprises a container 26 having a bimetallic strip 27- provided with aheater element 28 which is connected in parallel with the electrodes 2'by leads 22. Said bimetallic strip 27 is connected into lead 16 of theheating circuit and carries one of the two contacts 10. With normalconditions of gas pressure present in the gaseous electric dischargedevice 1 the potential on heater 28 is suflicient for said heater 28 toradiate enough heat to maintain bimetallic strip 27 in a bent position,in which position contacts 10 are separated. If the gas pressure ingaseous electric discharge device 1 decreases less heat radiates fromelement 28 as hereinbefore described and bimetallic strip 2'7 resumesits closed position in which position contacts 10 touch each other toput heater element 12 in the circuit which heats the gas evolvingmaterial.

While we have shown and described particular embodiments of ourinvention it will be understood that such illustration and descriptionis primarily for purposes of disclosure and that numerous substitutions,modifications and changes in the forms and details of the device and inits use and operation may be made by those skilled in the art withoutdeparture from the broad spirit and scope of the invention. For example,different governors for connecting into and out of circuit the heatingmeans 12 of the gas evolving material may be used instead of thoseshown; any suitable form of gas evolving material may be used, or theheater element 12 may operate, as does the well known Moore valve, toopen and close a reservoir of gas replenishments.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In combination, a luminescent electric discharge device, coniprisinga container, electrodes for said container, a luminescent gas filling insaid container, a gas supply'chamber for said container, a gas evolvingmaterial in said chamber, means comprising a heating coil connected inparallel to said device to heat said gas evolving material and meansresponsive to changes in potential across said electric discharge devicefor controlling said heating means.

2. In combination, a luminescent electric discharge device, comprising acontainer, electrodes for said container, a luminescent gas filling insaid container, a gas supply chamber for said container, a gas evolvingmaterial in said chamber, a current source for said device, meanscomprising a heating coil connected to said source and in parallel tosaid device to heat said gas evolving material and means responsive tochanges in the potential of said electric discharge device forcontrolling said heating means.

3. In combination, an electric discharge device, comprising a container,electrodes for said container, agas filling in said container, a gassupply chamber for said container, a gas evolving material in saidchamber, a current source for said device, a series choke coil for saiddevice, means comprising a heating coil connected in parallel to saiddevice to heat said gas evolving material and means connected to saidsource through said series choke coil and responsive to changes in thepotential of said electric discharge device for controlling said heatingmeans.

4. In combination, an electric discharge device, comprising a container,electrodes for said container, a gas filling in said container, a gassupply chamber for said container, a gas evolving material in saidchamber, a current source for said device, a current ballasting deviceconnected to said source, means comprising a heating coil connected inparallel to said device to heat said gas evolving material and meansconnected to said source through said ballast device and responsive tochanges in the potential of said electric discharge device to controlsaid heating means.

MARCELLO PIRANI. HANS EWEST. MARTIN REGER.

